High-temperature coal gas purifying and cooling integrated system of smelting reduction furnace

Abstract

The utility model belongs to the technical field of smelting reduction furnace tail gas treatment, and particularly relates to a smelting reduction furnace high-temperature coal gas purification and cooling integrated system, which firstly utilizes a gas-solid separation module to carry out gas-solid separation on flue gas generated by a smelting reduction furnace, and then utilizes a coal gas cooling module to cool separated gas. The temperature of gas entering the fire tube waste heat boiler is reduced, and dust accumulation in a fire tube is avoided. According to the coal gas cooling module, the heat exchange pipes which are annularly arranged are arranged in the cooling cylinder, so that gas circulation is guaranteed, and meanwhile, the gas flowing through the cooling cylinder can be effectively cooled by introducing cooling liquid into the heat exchange pipes.

Description

Technical Field

[0001] The utility model belongs to the technical field of tail gas treatment of a smelting reduction furnace, and specifically relates to an integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace. Background Art

[0002] The cylindrical reduction furnace is a molten reduction ironmaking device. During the operation of the cylindrical reduction furnace ironmaking production process, cylindrical reduction furnace gas will be generated. The cylindrical reduction furnace gas contains 12-24% CO, the gas temperature is up to 1650℃, and the dust content is>20g / Nm 3 , pressure 80kPa.

[0003] In order to utilize the above-mentioned cylindrical reduction furnace gas, Chinese patent document CN211035975U (201921427799.7) discloses a smelting reduction furnace gas recycling system, which includes: a vaporization flue, a cyclone dust collector, a waste heat boiler, a bag dust collector, and a pressure regulating valve group connected in sequence, wherein the outlet of the pressure regulating valve group is respectively connected to a pulverized coal preparation device, a hot blast furnace, and a drying kiln, and the inlet of the vaporization flue is connected to the smelting reduction furnace. Internal recycling is realized in the entire process. Not only is the physical sensible heat of the high-temperature coal gas fully utilized, but the chemical heat of the coal gas is also fully released, which greatly reduces the energy consumption of the entire process and achieves the purpose of energy saving and consumption reduction. However, the above structure cannot control the temperature of the coal gas entering the waste heat boiler. Since the temperature of the coal gas needs to be controlled within a certain range to ensure that the fire tube boiler does not accumulate ash, the above system cannot be applied to the fire tube boiler. Utility Model Content

[0004] The utility model aims to solve the above problems and provides an integrated system for purifying and cooling high-temperature coal gas in a smelting reduction furnace, which uses a coal gas cooling module to cool the gas separated by a gas-solid separation module before introducing it into a fire tube waste heat boiler.

[0005] The technical problem to be solved by the utility model is achieved by adopting the following technical scheme: a high-temperature coal gas purification and cooling integrated system for a smelting reduction furnace, the purification and cooling integrated system is connected to the inlet of a fire tube waste heat boiler, and comprises a gas-solid separation module and a coal gas cooling module connected in sequence;

[0006] The gas-solid separation module is used to perform gas-solid separation on flue gas;

[0007] The coal gas cooling module includes a cooling tube connected to the gas outlet of the gas-solid separation module and a heat exchange tube arranged in a ring shape along the circumference of the cooling tube. The heat exchange tube is arranged inside the cooling tube in parallel with the axial direction of the cooling tube. Inlet and outlet pipes communicating with the outside of the cooling tube are arranged at the upper and lower ends of the heat exchange tube.

[0008] Preferably, the coal gas cooling module includes a plurality of parallel cyclone dust collectors, the inlet of the cyclone dust collectors is connected to the flue gas outlet of the smelting reduction furnace, and the air outlets of the cyclone dust collectors are respectively connected to the cooling cylinders. By arranging a plurality of parallel cyclone dust collectors, the dust removal efficiency is improved.

[0009] Preferably, the utility model further comprises a transition duct arranged between the gas-solid separation module and the coal gas cooling module, and the air outlets of the cyclone dust collectors are respectively connected to the transition ducts;

[0010] The transition duct is provided with a heat-resistant layer and the gas separated by the cyclone dust collector is collected and transported by the transition duct.

[0011] Preferably, the coal gas cooling module of the utility model comprises four vertical cyclone dust collectors arranged in a ring shape. Arranging the vertical cyclone dust collectors in a ring shape helps to save space.

[0012] Preferably, the utility model further comprises a steam drum connected to the inlet and outlet pipes of the heat exchange tube, wherein the steam drum and the heat exchange tube are connected by an ascending pipe and a descending pipe;

[0013] The steam drum is located above the heat exchange tube, and a steam outlet is provided above the steam drum. The steam drum is arranged above the heat exchange tube, and the steam drum and the heat exchange tube are connected by an ascending tube and a downcomer to form a water circulation of the steam drum itself. The water circulation of the steam drum is a convective heat circulation. The hot water (steam) generated by the heat exchange tube enters the steam drum through the ascending tube. The hot water has a light mass and exchanges heat in the process of moving upward, and part of the water is converted into gas; the cold water in the steam drum is replenished to the heat exchange tube through the downcomer under the action of gravity. The circulation of water between the steam drum and the heat exchange tube under the action of siphon is the self-circulation of the steam drum. The amount of steam rising is positively correlated with the amount of water descending.

[0014] Preferably, the steam drum is connected to the fire tube waste heat boiler, the steam drum is located above the fire tube waste heat boiler, and the steam drum and the fire tube waste heat boiler are connected by an ascending pipe and a descending pipe. The steam drum is arranged above the fire tube waste heat boiler, and the steam drum and the fire tube waste heat boiler are connected by an ascending pipe and a descending pipe, so as to form a water circulation of the steam drum itself. The circulation of water between the steam drum and the fire tube waste heat boiler under the action of siphon also adopts the self-circulation of the steam drum.

[0015] Preferably, the heat exchange tube is spaced apart from the inner wall of the cooling tube, so as to ensure that the heat exchange tube is in full contact with the gas flowing through the cooling tube, thereby improving the heat exchange efficiency.

[0016] Preferably, in the present invention, the flow direction of the heat exchange medium in the heat exchange tube is opposite to the flow direction of the gas in the cooling cylinder, so that the heat exchange effect is enhanced through convection.

[0017] Compared with the prior art, the beneficial effect of the utility model is: the utility model first uses the gas-solid separation module to separate the flue gas generated by the smelting reduction furnace into gas and solid, and then uses the coal gas cooling module to cool the separated gas, so as to reduce the temperature of the gas entering the fire tube waste heat boiler and avoid ash accumulation in the fire tube.

[0018] The gas cooling module is equipped with heat exchange tubes arranged in a ring shape in the cooling tube to ensure gas fluidity. At the same time, cooling liquid is introduced into the heat exchange tubes to effectively cool the gas flowing through the cooling tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural schematic diagram of an integrated system for purifying and cooling high-temperature coal gas in a smelting reduction furnace in an embodiment of the utility model;

[0020] Figure 2 This is a structural schematic diagram of a gas cooling module in an embodiment of the utility model;

[0021] Figure 3 This is a schematic diagram of the arrangement of heat exchange tubes of a gas cooling module in an embodiment of the utility model;

[0022] Figure 4 It is a three-dimensional diagram of the integrated system for purifying and cooling high-temperature coal gas in a smelting reduction furnace in an embodiment of the utility model;

[0023] In the figure, 1 is a gas-solid separation module, 2 is a gas cooling module;

[0024] 21 cooling tube, 22 heat exchange tube, 23 inlet and outlet pipes;

[0025] 3 transition pipes, 4 steam drums. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0027] like Figure 1 and Figure 2 As shown, a high-temperature coal gas purification and cooling integrated system for a smelting reduction furnace is provided. The purification and cooling integrated system is connected to the inlet of a fire tube waste heat boiler, and comprises a gas-solid separation module 1 and a coal gas cooling module 2 connected in sequence. The coal gas cooling module 2 is located above the gas-solid separation module 1.

[0028] The gas-solid separation module 1 is used to perform gas-solid separation on flue gas.

[0029] like Figure 2 and Figure 3As shown, the coal gas cooling module 2 includes a cooling tube 21 connected to the gas outlet of the gas-solid separation module 1 and a heat exchange tube 22 arranged in a ring shape along the circumference of the cooling tube 21. The heat exchange tube 22 forms an annular channel for coal gas to pass through. The heat exchange tube 22 is arranged inside the cooling tube 21 in parallel with the axial direction of the cooling tube 21. The heat exchange tube 22 is spaced apart from the inner wall of the cooling tube 21. Inlet and outlet pipes 23 communicating with the outside of the cooling tube 21 are arranged at the upper and lower ends of the heat exchange tube 22. The flow direction of the heat exchange medium in the heat exchange tube 22 is opposite to the flow direction of the gas in the cooling tube 21.

[0030] like Figure 4 As shown, the coal gas cooling module 2 includes a plurality of cyclone dust collectors connected in parallel, and the air outlets of the cyclone dust collectors are respectively connected to the cooling cylinders 21 .

[0031] like Figure 1 and Figure 4 As shown, the integrated system for purifying and cooling high-temperature coal gas in a smelting reduction furnace further includes a transition pipe 3 arranged between the gas-solid separation module 1 and the coal gas cooling module 2, and the air outlets of the cyclone dust collectors are respectively connected to the transition pipe 3.

[0032] A heat-resistant layer is arranged inside the transition duct 3 .

[0033] The coal gas cooling module 2 includes four vertical cyclone dust collectors arranged in a ring shape.

[0034] like Figure 1 As shown, the integrated system for purifying and cooling high-temperature coal gas in the molten reduction furnace also includes a steam drum 4 connected to the inlet and outlet pipes 23 of the heat exchange tube 22. The steam drum 4 contains a coolant, which is water. The steam drum 4 and the heat exchange tube 22 are connected by an ascending pipe and a descending pipe.

[0035] The steam drum 4 is located above the heat exchange tube 22 .

[0036] The steam drum 4 is connected to the fire tube waste heat boiler. The steam drum 4 is located above the fire tube waste heat boiler. The steam drum 4 and the fire tube waste heat boiler are connected by an ascending pipe and a descending pipe.

[0037] The integrated system for purifying and cooling high-temperature coal gas in the smelting reduction furnace also includes a superheater connected to the steam outlet of the steam drum 4 .

[0038] Compared with the prior art, the integrated system for purifying and cooling the high-temperature coal gas of the smelting reduction furnace of this embodiment has the advantages of high quality of recovered steam, high dust removal efficiency, environmental friendliness, energy saving and green emission reduction.

[0039] Working principle: The flue gas from the settling chamber of the molten reduction furnace enters four parallel cyclone dust collectors radially from the central air inlet pipe. The cyclone dust collector has a high-temperature, pressure-resistant, efficient, heat-insulating and wear-resistant lining. The flue gas forms a vortex through the guide vanes, and the centrifugal force generated throws the flue gas to the inner wall of the cyclone dust collector, and the separated dust falls into the ash bin along the inner wall. The roughly purified coal gas is discharged through the inner cylinder located at the top of the cyclone dust collector. The flue gas flows out from the top of the four cyclone dust collectors and converges to the transition duct 3 to enter the downstream waste heat boiler system.

[0040] Since the flue gas inlet temperature of the cyclone dust collector is 747-774℃, the internal lining of the cyclone dust collector is refractory. The upper part of the cyclone dust collector is a cyclone tube, and the lower part is an ash collection bin. The pressure shell material of the cyclone dust collector is Q345R material, the outer diameter of a single cyclone tube is D3200mm, and the tube height is 14.3m; the outer diameter of the ash collection bin is D2400mm, and the height is 4.6m; the cyclone dust collector is equipped with lightweight insulation castable + wear-resistant corundum castable, and the heat-resistant lining has good insulation performance, which can ensure that the temperature of the equipment shell is ≤80℃.

[0041] The material of the inlet and outlet main pipes of the four cyclone dust collectors is DN3400, taking into account the flue gas balance between the cyclones. The main inlet manifold structure is extremely simple and easy to inspect and maintain. The equipment parameters are as follows:

[0042] The total dust removal efficiency η ≥ 85%;

[0043] Total pressure drop ΔP≤1800Pa (excluding inlet and outlet pipe resistance);

[0044] The cyclone dust collector is a vertical structure, covers an area of ​​about 16mx17m, and is set up outdoors. The gas-solid separation module system is divided into 4 sets of cyclone cylinders, and each cyclone cylinder is equipped with a bottom ash bin.

[0045] The gas-solid separation module control and monitoring are centrally set up in the smelting reduction furnace control room to control and monitor the ash bin level.

[0046] In order to control the temperature of the coal gas entering the fire tube waste heat boiler, the transition pipe 3 is connected to the cooling tube 21. Since the cooling tube 21 is provided with a heat exchange tube 22 arranged in a ring shape, the heat exchange medium is introduced into the heat exchange tube 22 to cool the coal gas passing through the cooling tube 21. The cooling tube 21 is used as a front vaporization flue with a diameter of about D4100mm and a length of about 16m.

[0047] The gas-liquid mixture steam bag 4 in the heat exchange tube 22 realizes gas-liquid separation, realizing the recycling of steam, while the liquid enters the heat exchange tube 22 for circulation and cooling.

[0048] The fire tube boiler is a dual-channel single-pressure two-stage type. The hot flue gas in the fire tube waste heat boiler flows through the fire tube, which is beneficial to the safe operation of the gas system.

[0049] The high-temperature flue gas at the outlet of the cyclone dust collector enters from the bottom of the cooling tube 21, and after countercurrent heat exchange with the heat exchange medium in the heat exchange tube 22, the flue gas temperature drops to 433-445°C, and is then led to the upper inlet of the fire tube boiler. The flue gas temperature after heat exchange in the fire tube boiler is controlled to between 150 and 200°C to ensure the air intake safety of the subsequent dry dust removal facilities.

[0050] A medium-pressure steam drum is set on the top platform of the waste heat boiler. The steam drum is connected to the double-channel fire tube boiler through risers and downcomers. The waste heat boiler system adopts full natural circulation.

[0051] The boiler feed water sent from the external pipeline network enters the steam drum through the pressure regulating valve group. The desalted water in the steam drum enters the double-channel boiler body through the downcomer to exchange heat with the hot flue gas. The formed steam-water mixture enters the steam drum through the riser. The hot water after the steam and water separation in the steam drum continues to enter the boiler through the downcomer for heat exchange. The saturated steam separated from the hot water in the steam drum and the saturated steam generated from the vaporization flue area are combined and enter the waste heat boiler superheater for overheating.

[0052] The superheater will superheat the 4.4MPa, 173.5t / h (150t / h+23.5t / h) saturated medium-pressure steam generated by the gas cooling module and the waste heat boiler system and supply it to the steam turbine for power generation. The steam parameters after superheating are 4.1MPa, 435℃, the normal steam output is ~177t / h, and the maximum steam generation is 193.5t / h.

[0053] The diameter of the superheated steam main steam pipeline is DN300, the pipeline material is 15GrMoG, and the pipeline standard is GB5310-2017. This area will send the superheated steam overhead to 1m outside the regional framework. The insulation is made of aluminum silicate wool products, and the protective layer is galvanized iron sheet.

Claims

1. An integrated system for purifying and cooling high-temperature coal gas in a smelting reduction furnace, characterized in that: The integrated purification and cooling system is connected to the inlet of the fire tube waste heat boiler and comprises a gas-solid separation module (1) and a coal gas cooling module (2) which are connected in sequence; The gas-solid separation module (1) is used to perform gas-solid separation on flue gas; The coal gas cooling module (2) comprises a cooling tube (21) connected to the gas outlet of the gas-solid separation module (1) and a heat exchange tube (22) arranged in a ring shape along the circumference of the cooling tube (21); the heat exchange tube (22) is arranged inside the cooling tube (21) in parallel with the axial direction of the cooling tube (21); and inlet and outlet pipes (23) communicating with the outside of the cooling tube (21) are arranged at the upper and lower ends of the heat exchange tube (22).

2. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 1 is characterized in that: The coal gas cooling module (2) comprises a plurality of cyclone dust collectors connected in parallel, and the air outlets of the cyclone dust collectors are respectively connected to the cooling cylinders (21).

3. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 2 is characterized in that: It also includes a transition duct (3) arranged between the gas-solid separation module (1) and the coal gas cooling module (2), and the air outlets of the cyclone dust collectors are respectively connected to the transition duct (3); A heat-resistant layer is provided inside the transition pipe (3).

4. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 2, characterized in that: The coal gas cooling module (2) comprises four vertical cyclone dust collectors arranged in a ring shape.

5. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 1 is characterized in that: It also includes a steam drum (4) connected to the inlet and outlet pipes (23) of the heat exchange tube (22), wherein the steam drum (4) and the heat exchange tube (22) are connected by an ascending pipe and a descending pipe; The steam drum (4) is located above the heat exchange tube (22).

6. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 5 is characterized in that: The steam drum (4) is connected to the fire tube waste heat boiler. The steam drum (4) is located above the fire tube waste heat boiler. The steam drum (4) and the fire tube waste heat boiler are connected by an ascending pipe and a descending pipe.

7. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 1 is characterized in that: The heat exchange tube (22) is spaced apart from the inner wall of the cooling tube (21).

8. The integrated system for purifying and cooling high-temperature coal gas of a smelting reduction furnace according to claim 1 is characterized in that: The flow direction of the heat exchange medium in the heat exchange tube (22) is opposite to the flow direction of the gas in the cooling cylinder (21).

Images